Diurnal Variation of Serum 25 (OH) D3 , Calcium and Phosphorus in Type 2 Diabetes Mellitus

Diurnal variation, an outgrowth of chronobiology, is the inferential statistical mapping of structures in variables; in and around us, consisting of rhythms chaos and trends. Type-2 diabetes mellitus is a metabolic disorder with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action or both. The diurnal time structure of serum 25(OH) D3 and calcium may relate to the prevention and chronotherapeutic efficacy and management of type 2 diabetes mellitus. To our knowledge, the diurnal variation of serum 25(OH) D3 has not yet been reported in type 2 diabetic patients. The present study was planned to evaluate the diurnal variation of serum 25(OH) D3 , calcium and phosphorus levels in type 2 diabetic patients. Ten clinically healthy volunteers and ten diagnosed patients of type 2 diabetes mellitus of similar age groups were synchronized for one month with diurnal activity from about 06:00 to about 22:00 and nocturnal rest. All subjects took their meals three times daily without any change in their usual fluid intake. Blood sample were collected into plain and sterile vials under quality control procedures from each participant at every 6 hour. Serum 25(OH) D3 , serum Ca++, serum PO4 , FBS and PPBS levels were estimated. A marked diurnal variation in serum 25(OH) D3 was recorded in healthy subjects (P=0.030). Similarly, a circadian rhythm of borderline statistical significance was also recorded for vitamin D in diabetic patients (P=0.083) and in healthy participants for serum calcium (P=0.070), phosphorus (P=0.102), and the calcium-phosphorus ratio (P=0.091) by the Two way ANOVA analysis. In addition, the amplitude and acrophase differed from healthy participants in diabetic patients for studied variables with a change of MESOR for calcium-phosphorus ratio. Mapping the broader time structure of different physiological variables investigated herein may be helpful in understanding the treatment and prevention of diabetic mellitus. Key words: Serum 25(OH) D3 , Calcium, Phosphorous, Type 2 Diabetes mellitus